High or Low? How to Do a Hair Porosity Test

What is Hair Porosity?

Hair porosity is determined by the structure of the hair cuticle, which is the outermost layer of the hair strand. The cuticle consists of overlapping cells that form a protective barrier. The condition and arrangement of these cells dictate how easily moisture and nutrients can penetrate the hair shaft.

Low porosity hair has a tightly packed cuticle layer, which makes it difficult for moisture to penetrate, and the products you apply may sit on the hair rather than being absorbed and your hair being easily weighed down by products.

Medium porosity hair has a slightly raised cuticle layer. This hair type is the most balanced, and is generally the easiest to manage and style.

High porosity hair has a raised and widely spaced cuticle layer. It absorbs moisture quickly, but loses it just as fast. This hair type tends to be more prone to frizz, dryness, and damage.

Hair Porosity Tests

There are a few simple at-home tests you can use to determine your hair’s porosity.

1. The Float Test: Take a few strands of clean, dry hair and place them in a bowl of water. If your hair floats, you likely have low porosity hair. If it sinks slowly, you have medium porosity hair. And if it sinks quickly, you have high porosity hair. Easy!
2. The Slide Test: Take a strand of hair and slide your fingers up the shaft from the ends towards the scalp. If you feel little resistance and your fingers glide smoothly, your hair is likely high porosity. If you feel some resistance but can still slide your fingers easily, you have medium porosity hair. If there is a lot of resistance and your fingers don't slide easily, your hair is likely low porosity.